The "HI" and "LO" are documented as High Current and Low Current. It looks
like the HI is for the audio, the LO is for the eproms (if jumpered via the
dip shunt at 8A on the audio/color board)..
As for the sync -- there are two jumpers on the board -- one for "video"
polarity (RGB) and one for sync polarity. Looks like you'll want to cut
the "sync" jumper to get negative sync.
Kurt
> Hi all,
>
> I picked up an untested Venture board which I'm testing out on my rig. I've
> gotten the power lines hooked up OK, and I'm getting pulses on the composite
> sync line, so at least *some* of the circuitry is working. For some reason,
> the board pinouts are showing 12V(hi) and 12V(lo) - I'm feeding 12V to both
> pins, although I wonder if that's correct. Does anyone know what the board
> is really expecting on those lines? I've never seen a board that asked for
> hi and lo versions of the same voltage...
>
> I've read values with my DMM from the RGB lines and from the composite sync
> line, and they look a little odd. The R,G,B lines read around 4.5-4.9 VDC,
> which seems higher than other boards, even if the board were generating a
> pure white screen. The pulsing sync line is reading 0.65V, which leads me to
> believe that it's positive sync, not negative, so I'm thinking that I'll
> have to invert it.
>
> What would typical values be for RGB/CS when read with a DMM on a board?
> Sadly, I don't have a scope, so I can't really see what the signals look
> like. I don't want to just start hooking things up to my monitor if the
> voltages are way out of range.
>
> Thanks in advance for any information,
>
> Drew
>
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Received on Sun Dec 30 17:03:05 2001
This archive was generated by hypermail 2.1.8 : Tue Dec 02 2003 - 17:51:28 EST